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crazy_fingers84
Apr 25, 2008, 4:26 PM
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A friend of mine set their slackline up earlier this week and the damn thing broke on her. She took these pictures of the faulty carabiner. I am amazed that the carabiner failed before the webbing broke.
I wish there was a picture of the half of the carabiner that is missing, but when the slackine broke it launched so far that she could not find it anywhere.
To explain the situation, the slackline was set up using 5 carabiners in a 5:1 pully system. The line was pulled very tight, and the person walking it at the time of failure was about 250+ lbs. She said when the line broke, "it was like a gun shot going right past their faces". It is incredible that nobody was injured badly. The person walking was hit in the foot on a ricochet and has a pretty swollen foot, nothing broken though.
The history of the carabiner is a little foggy. . . it was bootied at the NRG last year. I guess it wasn't good enough to climb on. . . this is a hard lesson learned. I find this very troubling because every time I set my line up, I picture the carabiner hurtling toward my face. . .
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epoch
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Apr 25, 2008, 4:39 PM
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That webbing has a rating of about 5000 lbf/22.2kN. The caribiner around 5395lb/24kN.
Depending on how it was tensioned it may have been crossloaded. But since we can only assume as to how the system was rigged we can only assume the reasons it may have broke. Being a bootied biner also, as you stated, brings into question of the history of that particular biner. Maybe one of the engineering types can provide a better analysis of the possibility of failure based on where the biner broke.
I use an exclusive set of caribiners for slacklining and purchased them just for the set up that I have.
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reg
Apr 25, 2008, 4:47 PM
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just a presumption of course but i agree with you. blue tape indicates former use leading or tr'ing - could have been dropped and then relagated to bail/racking status then used for the line leading to failure.
now that we have said what we think - let's hear from the op about the biner!
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crazy_fingers84
Apr 25, 2008, 5:03 PM
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the blue tape was just to distinguish a slackline only carabiner from the rest of her climbing gear. she only ever used that biner for slacklining, but like i said . . . it was bootied. i believe that carabiner was found clipped into a petzl mini triaxion at the NRG a year ago. the carabiner (and triaxion) were found sitting on the ground . i have no idea what happened to the carabiner before she acquired it. i think that it is a black diamond carabiner, but i am unsure what model it is. the carabiner was probably loaded triaxely (sp?). it is also unclear as to whether the gate was open.
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majid_sabet
Apr 25, 2008, 6:26 PM
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I wonder how they guys really stay alive doing what they do.
I took this photo in my gym for reference to point out biner cross loading.
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shockabuku
Apr 25, 2008, 6:39 PM
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??crossloading??
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sterlingjim
Apr 25, 2008, 6:43 PM
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Looks like classic open gate failure to me.
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troutboy
Apr 25, 2008, 7:28 PM
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shockabuku wrote: majid_sabet wrote: to point out biner cross loading. [IMG]http://b.imagehost.org/0621/04-06-07_2000.jpg[/IMG] [IMG]http://b.imagehost.org/0621/04-06-07_1957.jpg[/IMG] [IMG]http://b.imagehost.org/0621/04-06-07_1959.jpg[/IMG] ??crossloading??
TS
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marc801
Apr 25, 2008, 7:32 PM
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Like shockabuku implied, none of those biners in your photos are cross-loaded. There are some other funky things going on, but cross-loading isn't one of them.
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xtrmecat
Apr 25, 2008, 7:43 PM
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I see some loads on that locker that are very bad. Maybe warrants another look? I know it would fail much below the rated strength.
Bob
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majid_sabet
Apr 25, 2008, 7:57 PM
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I am sorry boys but, those biners are loaded from several directions and the main tension is not along the axis line where it should be.
Edit to add; since his biner failed while slacking and not in climbing, this could also prove that notch on the gate did not engaged with the pin as I had been saying it in the LAB.
correct loading ( A)
Multi directional loading ( B)
(This post was edited by majid_sabet on Apr 25, 2008, 9:10 PM)
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majid_sabet
Apr 25, 2008, 8:04 PM
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epoch wrote: That webbing has a rating of about 5000 lbf/22.2kN. The caribiner around 5395lb/24kN. Depending on how it was tensioned it may have been crossloaded. But since we can only assume as to how the system was rigged we can only assume the reasons it may have broke. Being a bootied biner also, as you stated, brings into question of the history of that particular biner. Maybe one of the engineering types can provide a better analysis of the possibility of failure based on where the biner broke. I use an exclusive set of caribiners for slacklining and purchased them just for the set up that I have.
Most webbings are rated around 4000 to 4400 lbs. Generally, you rate them about 18 KN ( with knot).
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jakedatc
Apr 25, 2008, 8:40 PM
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majid_sabet wrote: I am sorry boys but, those biners are loaded from several directions and the main tension is not along the axis line where it should be. Edit to add; since his biner failed while slacking and not in climbing, this could also prove that notch on the gate may not did not engaged with the pin as I had been saying in the LAB. correct loading ( A) Multi directional loading ( B) [IMG]http://b.imagehost.org/0623/loaded.jpg[/IMG] [IMG]http://b.imagehost.org/0623/load1_2.jpg[/IMG]
Multi directional loaded and crossloaded are 2 different things. Crossloaded in my experience is the spine or gate perpendicular to the load.
It looks like a classic open gate as Jim said.. Why they wouldn't be using lockers on a slack line to prevent just that isn't smart.. at least have non lockers op/opposed
from a standard D biner
Strength major axis open 9 kilonewtons
(This post was edited by jakedatc on Apr 25, 2008, 8:42 PM)
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SantaCruzClimber
Apr 25, 2008, 9:36 PM
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After reading this thread im starting to wonder how safe my line is, i always imagined should a biner fail on me, the friction of the line wrapping so many times would slow it enough that i wouldent get pegged in the head. I do not use lockers.
Any tips on rigging, or common mistakes i should have in mind ? Readings?
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endercore
Apr 25, 2008, 9:57 PM
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The webbing I use as an anchor for my line broke the other day.
thankfully I had some excess line friction wrapped around the tree so that when my anchor snapped I didn't have the whole system snapping back towards me.
for anyone that is interested- the webbing most probably broke from rubbing against the bark of the tree it was around.
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irregularpanda
Apr 25, 2008, 10:09 PM
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SantaCruzClimber wrote: I do not use lockers. Any tips on rigging, or common mistakes i should have in mind ? Readings?
Use lockers, also epoch said this earlier "I use an exclusive set of caribiners for slacklining and purchased them just for the set up that I have. " Which is a great idea, and angry said to use steel biners......... which lets you load your carabiner from several directions.
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majid_sabet
Apr 25, 2008, 10:35 PM
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SantaCruzClimber wrote: After reading this thread im starting to wonder how safe my line is, i always imagined should a biner fail on me, the friction of the line wrapping so many times would slow it enough that i wouldent get pegged in the head. I do not use lockers. Any tips on rigging, or common mistakes i should have in mind ? Readings?
By just looking at the way you guys rig, there are so many problems with your systems and looks like most of you follow each other on wrong rigging tips.Now,even if you use locking biner, you are still applying tensions from several point to the biners. When you are using a fat knot on that webbing to attach it to biner. you are applying tensions and forces away from the axis line. You could tie your webbing to a steel rap ring then use the rap ring to connect it to biner.This way, you are using a smaller diameter attachment point and the load stays in the axis line.
Also, each leg of the anchor should have less than 120 degree when attached to biner. Whatever you do, make sure the tension is not loading the biner from corners as I pointed earlier.
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crazy_fingers84
Apr 25, 2008, 10:37 PM
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the biner that broke here was on the non-tightening side of the line. a was set up to always be on the non-tightening side because there is pretty much a permanent girth-hitch on the carabine. nothing slowed it down when it failed at this point. there is so much tension in some slackline systems that i think the even if only a piece of webbing hit you, it could do some damage to you. . . let alone a piece of flying carabiner.
i will say that the picture majid showed of the slackline is exactly how this one was set up. this is a really standard way to set up a slackline, and i have never really had much concern about it loading a carabiner incorrectly. i guess climbing gear sometimes carries a misconception about being unbreakable. . .
doesnt seem like it would be a problem to load it multi-directionally as long as the biner is a few feet away from the anchoring point. when the biner is loaded really close to the anchor, the direction of pull is outward at two points in addition to the direction of pull from the slackline.
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petsfed
Apr 25, 2008, 10:51 PM
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crazy_fingers84 wrote: the biner that broke here was on the non-tightening side of the line. a was set up to always be on the non-tightening side because there is pretty much a permanent girth-hitch on the carabine. nothing slowed it down when it failed at this point. there is so much tension in some slackline systems that i think the even if only a piece of webbing hit you, it could do some damage to you. . . let alone a piece of flying carabiner.
I had an anchor sling fail on me a few years ago. The carabiner that flew thirty feet into my knee only grazed me, but it left one hell of a bruise. I doubt I'd be walking today if it had hit me dead on.
To the topic at hand: the stretch-relax cycles on a slackline will occasionally open a carabiner (I've watched this a few too many times to doubt it) so I don't walk on my line until every carabiner is a locker screwed shut. My tightening system is different, but it is backed up by the tightening system you can see in majid's post, which is rigged entirely with lockers in my system (and with an overhand on a bight instead of the clove hitch that m_s has).
Judging by the photo, this looks like an open gate failure, so replace the crabs in that location with lockers (I've found autolockers won't unscrew with vibration of the line, so that may be worth considering).
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majid_sabet
Apr 25, 2008, 10:59 PM
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petsfed wrote: crazy_fingers84 wrote: the biner that broke here was on the non-tightening side of the line. a was set up to always be on the non-tightening side because there is pretty much a permanent girth-hitch on the carabine. nothing slowed it down when it failed at this point. there is so much tension in some slackline systems that i think the even if only a piece of webbing hit you, it could do some damage to you. . . let alone a piece of flying carabiner. I had an anchor sling fail on me a few years ago. The carabiner that flew thirty feet into my knee only grazed me, but it left one hell of a bruise. I doubt I'd be walking today if it had hit me dead on. To the topic at hand: the stretch-relax cycles on a slackline will occasionally open a carabiner (I've watched this a few too many times to doubt it) so I don't walk on my line until every carabiner is a locker screwed shut. My tightening system is different, but it is backed up by the tightening system you can see in majid's post, which is rigged entirely with lockers in my system (and with an overhand on a bight instead of the clove hitch that m_s has). Judging by the photo, this looks like an open gate failure, so replace the crabs in that location with lockers (I've found autolockers won't unscrew with vibration of the line, so that may be worth considering).
You should always warp a T shirt over hardware that are under massive tension. I also had seen riggers leave some rope or webbing to hang after the biner. This hanging rope (cord, sling, ..) causes the webbing or cord that is under tension not to fly if system fails.
Other option is to start the knot few feet away from the end and attach the end to a seperate anchor
(This post was edited by majid_sabet on Apr 25, 2008, 11:02 PM)
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jcrew
Apr 25, 2008, 11:02 PM
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like was said, probably an open-gate situation.
now, i don't know if people like using climbing gear for lines, but the state-of-the- highline rigs use steel rigging shackles and industrial span-sets/choke rings. the is no climbing gear in the picture except for bolt hangers...the biners are steel screw gate ovals, like angry said.
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jt512
Apr 25, 2008, 11:14 PM
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endercore wrote: The webbing I use as an anchor for my line broke the other day. thankfully I had some excess line friction...
Thankfully, it wasn't a highline.
Jay
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jt512
Apr 25, 2008, 11:17 PM
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Why do you guys use carabiners instead of quick links, which can be wrench tightened.
Jay
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petsfed
Apr 25, 2008, 11:34 PM
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jt512 wrote: Why do you guys use carabiners instead of quick links, which can be wrench tightened. Jay
Too cheap to go to that much trouble for a low line.
I know, that's a terrible reason, but I'm much more likely to get injured by falling off the line than if the line fails. I've never had a failure when anyone was on the line, but I guess there's a first time for everything. I'm in the process of reworking my system in favor of steel equipment, but its expensive and time consuming, so in the mean time I just check my gear more often than I used to.
Also, I've heard about the threads on quicklinks deforming under high load so that they're impossible to open again, and I don't like being forced to cut apart a system under load. Frankly, that seems needlessly reckless. Finally, the scale of a full sized oval is what makes the system go. Most quicklinks I've encountered are too small to use in the same way that I use the carabiners, and unless somebody can suggest a good system that uses only quicklinks, its not worth the somewhat dangerous experimental period as I figure out what works.
n.b. I only rig lowlines. The tallest I've ever rigged had one end 5 feet up, because the area was sloped and we'd bottom out otherwise. The other end was about 3 feet up. I'm not even going to consider a high line until I've had a chance to walk a few and learn what works best in that situation.
(This post was edited by petsfed on Apr 25, 2008, 11:36 PM)
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